/*
 * Copyright 2015 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package io.netty.example.http2.tiles;

import static io.netty.buffer.Unpooled.unreleasableBuffer;
import static io.netty.example.http2.Http2ExampleUtil.toByteBuf;
import io.netty.buffer.ByteBuf;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * Caches the images to avoid reading them every time from the disk.
 */
public final class ImageCache
{

    public static ImageCache INSTANCE = new ImageCache();

    private final Map<String, ByteBuf> imageBank = new HashMap<String, ByteBuf>(
            200);

    private ImageCache()
    {
        init();
    }

    public static String name(int x, int y)
    {
        return "tile-" + y + "-" + x + ".jpeg";
    }

    public ByteBuf image(int x, int y)
    {
        return imageBank.get(name(x, y));
    }

    private void init()
    {
        for (int y = 0; y < 10; y++)
        {
            for (int x = 0; x < 20; x++)
            {
                try
                {
                    String name = name(x, y);
                    ByteBuf fileBytes = unreleasableBuffer(
                            toByteBuf(getClass().getResourceAsStream(name))
                                    .asReadOnly());
                    imageBank.put(name, fileBytes);
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
        }
    }
}
